The conventional evaluation of the performance of a parallel computer system has been carried out by determining a parallel efficiency Epara(p, n) as follows:
                                          E            para                    ⁡                      (                          p              ,              n                        )                          ≡                              τ            ⁡                          (                              1                ·                n                            )                                                          τ              ⁡                              (                                  p                  ,                  n                                )                                      ·            p                                              (        1        )            wherein p represents the number of processors; and n the size of a problem. In order to determine a parallel efficiency Epara(p, n) in accordance with the expression (1), it is necessary that sequential processing time τ(l, n), which is a processing time during which the sequential processing is carried out, and parallel processing time τ(p, n), which is a processing time during which the parallel processing is carried out, be measured individually, If the parallel processing time τ(p, n) becomes long, it becomes difficult in some cases to measure the sequential processing time τ(l, n), which becomes longer than the parallel processing time,
In addition, if this parallel efficiency Epara(p, n) is low, i.e., if the performance of parallel processing is low, it is necessary to specify causes of hampering the improvement of the performance to improve, Therefore, it was necessary to further conduct measurement not less than one time to specify the causes of hampering the improvement of the performance with respect to the parallel processing and to determine their percentages.
In the conventional evaluation method, the quantitative relation between the causes of hampering the improvement of the performance and the parallel efficiency was not clear, so that it was difficult to determine how much each cause of hampering the improvement of the performance lowers the parallel efficiency.